IMMUNOLOGIC PARAMETERS IN SYSTEMIC SCLEROSIS

Background. Immunologic abnormalities seem to play an important role in systemic sclerosis (SSc). Methods. We studied the following immune parameters to get more insight into SSc: autoantibodies (antinuclear antibodies (ana ), anti-Scl-70, anticentromere antibodies (aca ) subsets of lymphocyte subpopulations and markers of their activation, as well as serum levels of il -2, the soluble il -2 receptor (sil -2r ), il -6 and its correlation to N-terminal procollagen-Ill propeptide (p iii p ), and finally, the il -6 production by SSc and normal dermal fibroblasts. Results. In patients with active SSc, we found a reduced number of cd 2+ T-lymphocytes and an increase in the expression of T-lymphocyte activation markers such as cd 25+ and cd 71+, hla -dr la, as well as elevated serum levels of sil -2lr and il -6. SSc fibroblasts did not produce more il -6 than normal fibroblasts in monolayer cultures. Conclusions. Our data show that a wide range of immunologic parameters are altered in SSc. In general, T-helper (th ) lymphocytes are activated possibly because of reduced T-suppressor (ts ) and natural killer (nk )-cell levels, TH may polyclonally stimulate B cells, which in turn produce higher amounts of autoantibodies. Our findings support the concept that TH cell-derived cytokines/growth factors stimulate matrix protein synthesis by fibroblasts, resulting in generalized fibrosis.